U.S. patent number 8,832,952 [Application Number 13/335,158] was granted by the patent office on 2014-09-16 for apparatus for measuring outer diameters of fuel rods of nuclear fuel assembly.
This patent grant is currently assigned to Kepco Nuclear Co., Ltd.. The grantee listed for this patent is Jin Man Joo, Dae Hee Kang, Soon Ki Kim, Jung Cheol Shin. Invention is credited to Jin Man Joo, Dae Hee Kang, Soon Ki Kim, Jung Cheol Shin.
United States Patent |
8,832,952 |
Shin , et al. |
September 16, 2014 |
Apparatus for measuring outer diameters of fuel rods of nuclear
fuel assembly
Abstract
Provided is an apparatus for measuring outer diameters of fuel
rods of a nuclear fuel assembly, in which the fuel rods are
standing upright and are used in a light water reactor. The
apparatus includes a support unit fixed to a floor at a lower
portion thereof so as to be kept insulated from vibrations caused
by external forces, a measuring unit mounted on the support unit
and moving up and down to measure the outer diameters of the fuel
rods, and a transducer cooperating with the measuring unit,
converting the measured outer diameters of the fuel rods into
electrical signals, and sending the converted signals to the
outside. Thus, the apparatus moves up and down to measure the outer
diameters of the fuel rods, so that it can accurately check
abnormalities in the outer diameters of the fuel rods.
Inventors: |
Shin; Jung Cheol (Daejeon,
KR), Kim; Soon Ki (Daejeon, KR), Joo; Jin
Man (Daejeon, KR), Kang; Dae Hee (Daejeon,
KR) |
Applicant: |
Name |
City |
State |
Country |
Type |
Shin; Jung Cheol
Kim; Soon Ki
Joo; Jin Man
Kang; Dae Hee |
Daejeon
Daejeon
Daejeon
Daejeon |
N/A
N/A
N/A
N/A |
KR
KR
KR
KR |
|
|
Assignee: |
Kepco Nuclear Co., Ltd.
(Daejeon, KR)
|
Family
ID: |
47437776 |
Appl.
No.: |
13/335,158 |
Filed: |
December 22, 2011 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20130008041 A1 |
Jan 10, 2013 |
|
Foreign Application Priority Data
|
|
|
|
|
Jul 8, 2011 [KR] |
|
|
10-2011-0067726 |
|
Current U.S.
Class: |
33/502 |
Current CPC
Class: |
G01B
7/12 (20130101); G21C 17/06 (20130101); G01B
5/08 (20130101); Y02E 30/30 (20130101) |
Current International
Class: |
G01B
1/00 (20060101) |
Field of
Search: |
;33/502,501.6,783,784,793 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
10-0375046 |
|
Mar 2003 |
|
KR |
|
10-2003-0081533 |
|
Oct 2003 |
|
KR |
|
Other References
English Language Abstract of KR 10-2001-0048791 A which is an
application publication of KR 10-0375046 B1. cited by applicant
.
English Language Abstract of KR 10-2003-0081533 A. cited by
applicant.
|
Primary Examiner: Guadalupe-McCall; Yaritza
Attorney, Agent or Firm: Rabin & Berdo, P.C.
Claims
What is claimed is:
1. An apparatus for measuring outer diameters of fuel rods of a
nuclear fuel assembly, the apparatus comprising: a support unit
disposed on a floor at a lower portion thereof; a measuring unit
mounted on the support unit and configured to move up and down to
measure the outer diameters of the fuel rods, the measuring unit
including a base mounted on the support unit and moving up and
down, a length adjustor mounted on the base, and a pair of contact
arms installed on the length adjuster and contacting with outer
circumferential surfaces of the fuel rods being measured, the pair
of contact arms having a predetermined length enough to contact
with at least two fuel rods at the same time; and a transducer
configured to convert the outer diameters measured by the
measurement unit of the fuel rods into electrical signals, and
configured to send the converted signals to the outside.
2. The apparatus as set forth in claim 1, wherein the transducer is
a linear variable differential transformer (LVDT).
3. The apparatus as set forth in claim 1, wherein the pair of
contact arms includes contact recesses formed in each contact
arms.
4. The apparatus as set forth in claim 1, wherein the measuring
unit further includes a coupler mounted on the length adjustor and
configured to hold the length adjustor firmly.
5. An apparatus for measuring outer diameters of fuel rods of a
nuclear fuel assembly, the apparatus comprising: a support unit
disposed on a floor at a lower portion thereof; a measuring unit
mounted on the support unit and moving up and down to measure the
outer diameters of the fuel rods, the measuring unit including a
base mounted on the support unit and moving up and down, a length
adjustor mounted on the base, a pair of contact arms installed on
the length adjuster and contacting with outer circumferential
surfaces of the fuel rods being measured, a fixture mounted on the
base, and a roller mounted on the fixture and configured to prevent
the fuel rod from moving in a left or a right direction; and a
transducer configured to convert the outer diameters measured by
the measurement unit of the fuel rods into electrical signals, and
configured to send the converted signals to the outside.
6. The apparatus as set forth in claim 5, wherein the measuring
unit further includes a cover mounted over a space between the
fixture and the length adjustor and coupled to the base.
7. The apparatus as set forth in claim 5, wherein the fixture
comprises: a fixture plate configured to support the fixture; a
first U-shaped bracket mounted on the fixture plate; and a second
U-shaped bracket mounted on the first U-shaped bracket and
configured to support the roller.
8. An apparatus for measuring outer diameters of fuel rods of a
nuclear fuel assembly, the apparatus comprising: a support unit
fixed to a floor at a lower portion thereof; a measuring unit
mounted on the support unit and configured to move up and down to
measure the outer diameters of the fuel rods; and a transducer
configured to convert the outer diameters measured by the
measurement unit of the fuel rods into electrical signals, and
configured to send the converted signals to the outside, wherein
the measuring unit includes a base mounted on the support unit and
configured to move up and down by a pneumatic motor installed on
the support unit, a length adjustor mounted on the base and having
a pair of contact arms configured to contact with outer
circumferential surfaces of the fuel rods being measured, a fixture
mounted on the base, a roller mounted on the fixture and configured
to prevent the fuel rod from moving in a left or a right direction,
a coupler mounted on the length adjustor and configured to hold the
length adjustor firmly, and a cover mounted over a space between
the fixture and the length adjustor, and coupled to the base,
wherein the transducer is a linear variable differential
transformer (LVDT), wherein the pair of contact arms has a
predetermined length enough to contact with at least two fuel rods
at the same time, and includes contact recesses formed in each
contact arms, and wherein the fixture comprises a fixture plate
configured to support the fixture, a first U-shaped bracket mounted
on the fixture plate, and a second U-shaped bracket mounted on the
first U-shaped bracket and configured to support the roller.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
The present application claims priority under 35 U.S.C. 119 to
Korean Patent Application No. 10-2011-0067726, filed on Jul. 8,
2011, the disclosure of which is expressly incorporated by
reference herein in its entirety.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates, in general, to an apparatus for
measuring outer diameters of fuel rods of a nuclear fuel assembly
and, more particularly, to an apparatus for measuring outer
diameters of fuel rods of a nuclear fuel assembly, capable of
moving up and down to measure the outer diameters of the fuel rods
to accurately check for abnormalities in the outer diameters of the
fuel rods, and rapidly and efficiently measuring the outer
diameters of the fuel rods without having to disassemble the
nuclear fuel assembly.
2. Description of the Related Art
Atomic power generation based on a light water reactor is designed
to generate energy via the fission of nuclear fuel, use the energy
to heat primary cooling water, transmits the energy of the heated
primary cooling water to secondary cooling water in a steam
generator to generate steam, convert the generated steam into
rotational energy with a steam turbine, and produces electricity
with a generator.
Generally, an apparatus for measuring the outer diameters of fuel
rods of a nuclear fuel assembly is used to measure the outer
diameters of the fuel rods that are standing upright in a fuel
storage pool of the light water reactor.
The outer diameters of the fuel rods are measured using such an
apparatus so as to check the fuel rods for abnormalities.
Examples of the related art include Korean Patent No. 10-0375046,
entitled "Gap measuring method for spent fuel rods and its device,"
Korean Patent Application Publication No. 10-2003-0081533, entitled
"Method for ultrasound measurement of layer thickness of cladding
tube for nuclear fuel," and so forth.
However, such conventional apparatuses have a problem in that they
cannot measure the outer diameter of each fuel rod over its
length.
Due to this incomplete measurement of the outer diameter, it is
impossible to accurately check the fuel rods for abnormalities and
therefore to prevent the life span of the fuel rods from being
reduced.
SUMMARY OF THE INVENTION
Accordingly, the present invention has been made keeping in mind
the problems occurring in the related art, and the present
invention is intended to provide an apparatus for measuring outer
diameters of fuel rods of a nuclear fuel assembly, capable of
moving up and down to measure the outer diameters of the fuel rods,
accurately checking the outer diameters of the fuel rods for
abnormalities, hence preventing a life span of the fuel rods from
being reduced, and rapidly and efficiently measuring the outer
diameters of the fuel rods without having to disassemble the
nuclear fuel assembly.
In order to achieve the objective of the invention, according to
one aspect of the present invention, there is provided an apparatus
for measuring the outer diameters of fuel rods of a nuclear fuel
assembly, in which the fuel rods are standing upright and are used
in a light water reactor. The apparatus comprises: a support unit
fixed to a floor at a lower portion thereof so as to keep the
apparatus in a secure state from vibrations caused by external
forces; a measuring unit mounted on the support unit and configured
to move up and down to measure the outer diameters of the fuel
rods; and a transducer configured to cooperate with the measuring
unit, configured to convert the measured outer diameters of the
fuel rods into electrical signals, and configured to send the
converted signals to the outside.
Here, the measuring unit may include: a base mounted on the support
unit and configured to move up and down by a pneumatic motor
installed on the support unit; and a length adjustor mounted on the
base, configured to cooperate with the transducer on one side
thereof, and having a pair of contact arms on the other side
thereof configured to contact with outer circumferential surfaces
of the fuel rods being measured.
The measuring unit can further include a fixture mounted on the
base and a roller aligned with the pair of contact arms in a
vertical direction.
Further, the transducer may be a linear variable differential
transformer (LVDT).
Also, the pair of contact arms may each have enough length to come
into contact with at least two fuel rods at the same time.
In addition, the pair of contact arms may include contact recesses
formed in both inner surfaces thereof, respectively.
According to the present invention of the aforementioned
configuration, the apparatus for measuring outer diameters of fuel
rods of a nuclear fuel assembly moves up and down to measure the
outer diameters of the fuel rods, so that it can accurately check
the outer diameters of the fuel rods for abnormalities and thus
prevent the life span of the fuel rods from being reduced.
Further, the apparatus can rapidly and efficiently measure the
outer diameters of the fuel rods without having to disassemble the
nuclear fuel assembly.
BRIEF DESCRIPTION OF THE DRAWINGS
The objects, features and further advantages of the present
invention will be more clearly understood from the following
detailed description in conjunction with the accompanying drawings,
in which:
FIG. 1 is a perspective view showing an apparatus for measuring the
outer diameters of fuel rods of a nuclear fuel assembly in
accordance with an exemplary embodiment of the present
invention;
FIG. 2 is a perspective view showing a measuring unit and a
transducer of the apparatus for measuring the outer diameters of
fuel rods of a nuclear fuel assembly in accordance with the
exemplary embodiment of the present invention;
FIG. 3 is an exploded perspective view showing the measuring unit
of the apparatus for measuring outer diameters of fuel rods of a
nuclear fuel assembly in accordance with the exemplary embodiment
of the present invention;
FIG. 4 is a perspective view showing a positional relationship
between the measuring unit and fuel rods in accordance with the
exemplary embodiment of the present invention; and
FIG. 5 is a top-down view showing the measuring unit according to
the exemplary embodiment of the present invention, in which fuel
rods are in contact with a pair of contact arms.
DETAILED DESCRIPTION OF THE INVENTION
Reference will now be made in greater detail to exemplary
embodiments of the invention with reference to the accompanying
drawings.
An apparatus for measuring outer diameters of fuel rods of a
nuclear fuel assembly in accordance with an exemplary embodiment of
the present invention is used to measure outer diameters of fuel
rods that stand upright and are used in a light water reactor, as
shown in FIGS. 1 to 3. Also, as shown in FIGS. 4 and 5, a measuring
unit 200 of the apparatus for measuring outers diameter of fuel
rods moves up and down in contact with the fuel rod 400, and
measures the outer diameter of the fuel rod 400.
As shown in FIG. 1, the apparatus for measuring outer diameters of
fuel rods of a nuclear fuel assembly includes a support unit 100, a
measuring unit 200, and a transducer 300.
The support unit 100 has a rectangular shape, and is fixed to a
floor at a lower portion thereof so as to keep the apparatus in
secure state from vibrations caused by external forces.
The measuring unit 200 is mounted on the support unit 100. The
measuring unit 200 is designed to be able to move up and down to
measure the outer diameters of the fuel rods 400. Pneumatic motors
(not shown) installed on the support unit 100 move the measuring
unit 200 freely in horizontal and vertical directions.
As shown in FIGS. 2 and 3, the measuring unit 200 includes a base
210 formed of a wide rectangular plate.
The base 210 is configured so that a fixture 240 having a stretched
"Z" shape is fixed to one end of the top surface thereof.
In detail, the fixture 240 includes a fixture plate 241 which is
formed of a plate that is smaller than the base 210, and is
configured so that the bottom surface thereof is fixed to the top
surface of the base 210. The fixture 240 also includes a first
U-shaped bracket 242 mounted on one end of the fixture plate 241 in
a vertical direction, and a second U-shaped bracket 243 coupled to
a top surface of the first U-shaped bracket 242 in a horizontal
direction.
The second U-shaped bracket 243 is provided with holes in both arms
thereof. A roller 230, which will be described below, is interposed
between the arms of the second U-shaped bracket 243, and then a pin
231 is inserted from one of the holes through the center of the
roller 230 into the other hole, so that the roller 230 is coupled
to the second U-shaped bracket 243.
The roller 230 is formed in the shape of a reel or a cylinder
having a groove of a predetermined depth in a radial inward
direction. The roller 230 brings the fuel rod 400 into close
contact with the groove thereof so as to prevent the fuel rod 400
from moving in left and right directions, so that the roller 230
allows the fuel rod 400 to be guided stably.
A length adjustor 220 is mounted on the base 210. The length
adjustor 220 connects with the transducer 300 on one side thereof,
and is provided with a pair of contact arms 221 on the other side
thereof which come into contact with outer circumferential surfaces
of the fuel rods 400 being measured.
To be specific, the length adjustor 220 is formed in a long rod
shape, and is placed on the top surface of the fixture plate
241.
The length adjustor 220 is coupled with a coupler 250 in the middle
of the contact arms thereof, so that the length adjustor 220 is
kept fixed. The coupler 250 is provided with a recess that is wide
enough to hold the length adjustor 220, thereby preventing the
length adjustor 220 from moving in left and right directions.
A cover 260 is coupled to one end of the top surface of the base
210 and mounted over a space between the fixture 240 and the
coupler 250.
The cover 260 has a U shape and is the same width as the base
210.
Meanwhile, as shown in FIG. 4, the length adjustor 220 is
configured so that the pair of contact arms 221 is installed on the
other side thereof and has a predetermined length enough to come
into contact with two or more fuel rods at the same time.
The pair of contact arms 221 is provided with contact recesses 222
in both inner surfaces thereof, respectively.
As shown in FIG. 5, the contact recesses 222 formed in the both
inner surfaces of the pair of contact arms 221 have an oval shape,
so that one of the fuel rods 400 comes into a space formed by the
contact recesses 222.
That is, the contact recesses 222 are to prevent the fuel rod 400
in the space between the contact recesses 222 from interfering with
another fuel rod being measured.
The measuring unit 200 is configured to cooperate with the
transducer 300 that converts the measured outer diameters of the
fuel rods 400 into electrical signals and then sends the signals to
the outside.
As shown in FIGS. 2 and 3, the transducer 300 is mounted on one
side of the length adjustor 220 that is one component of the
measuring unit 200 so as to correspond to the pair of contact arms
221.
The transducer 300 employs a linear variable differential
transformer (LVDT) that measures linear displacement and converts
it into an electrical signal. The LVDT has three solenoidal coils
placed end-to-end around a tube. The center coil is the primary,
and the two outer coils are the secondaries. Thus, a cylindrical
magnetic core moves along the center of the tube, and sends
information about the position of the fuel rod 400 being measured
to the outside.
Use and operation of the apparatus for measuring outer diameters of
fuel rods of a nuclear fuel assembly having the aforementioned
configuration according to the exemplary embodiment of the present
invention will be described below.
First, as shown in FIGS. 1 to 3, the measuring unit 200 is mounted
on the support unit 100 that is fixed to a floor and thus is kept
in a secured state from vibrations caused by external forces.
The mounted measuring unit 200 moves up and down by a pneumatic
motor or pneumatic motors installed on the support unit 100.
The measuring unit 200 is configured so that the fixture 240 having
a stretched Z shape is fixed to one end of the top surface of the
base 210. The fixture 240 is configured to be coupled with the
roller 230 in such a manner that the roller 230 is interposed
between the arms of the second U-shaped bracket 243, and then the
pin 231 is inserted into the holes formed in the arms of the second
U-shaped bracket 243.
The length adjustor 220 is placed on the top surface of the fixture
plate 241 with the transducer 300 mounted on one side of the length
adjustor 220 in advance.
The length adjustor 220 placed on the fixture plate 241 is fitted
into and coupled with the coupler 250 in the middle of the arms 221
thereof, so that the coupler 250 covers the width of the length
adjustor 220.
Finally, the cover 260 is mounted over a space between the fixture
240 and the coupler 250, and is firmly coupled to the top surface
of the base 210.
In the measuring unit 200 coupled in this way, the numerous fuel
rods 400 to be measured come into close contact with the pair of
contact arms 221 installed on one side of the length adjustor
220.
As shown in FIG. 4, since the measuring unit 200 mounted on the
support unit 100 is moved up and down by the pneumatic motors
installed on the support unit 100, the measuring unit 200 measures
the outer diameter of the fuel rod 400 while moving up and
down.
Thus, the measuring unit 200 sends information acquired when
measuring the outer diameter of the fuel rod 400 to the outside via
the transducer 300 mounted on the other side of the length adjustor
220.
Meanwhile, as shown in FIG. 5, in the state that one of the fuel
rods 400 has been brought into the space between the contact
recesses 222 formed in both inner surfaces of the pair of contact
arms 221, the pair of contact arms 221 measures the outer diameter
of the other fuel rod.
Further, when any overlooked or suspicious point is found in the
process of measuring the outer diameter of the fuel rod 400, the
upward and downward movements of the measuring unit 200 are
adjusted using the pneumatic motors installed on the support unit
100, so that it is possible to ensure more accurate
measurement.
When other unmeasured fuel rods are to be measured by the measuring
unit 200, the nuclear fuel assembly is rotated so that the other
unmeasured fuel rods are placed in a measuring position, and then
the other unmeasured fuel rods are measured in the aforementioned
sequence.
Thus, the measuring unit moves up and down to measure the outer
diameters of the fuel rods, so that it is possible to accurately
measure the abnormalities in the outer diameter of the fuel rod and
to prevent the life span of the fuel rods from being reduced.
Although an exemplary embodiment of the present invention has been
described for illustrative purposes, those skilled in the art will
appreciate that various modifications, additions and substitutions
are possible, without departing from the scope and spirit of the
invention as disclosed in the accompanying claims.
* * * * *